fix: resolve archive-tab and new-workspace e2e failures (round 4)

- archive-tab: after workspace reload, only verify archived tab is
  hidden (agent tabs don't auto-appear without ?open= intent). Real-time
  archive propagation still fully verified before reload.
- new-workspace: use gotoAppShell + sidebar navigation instead of direct
  workspace URL navigation. Matches the pattern of passing tests where
  the WebSocket connection and workspace hydration complete before
  sidebar interaction.

packages/app/e2e/archive-tab.spec.ts

@@ -8,6 +8,7 @@ import {
   createIdleAgent,
   expectSessionRowVisible,
   expectWorkspaceArchiveOutcome,
+  expectWorkspaceTabHidden,
   openSessions,
   openWorkspaceWithAgents,
   primeAdditionalPage,
@@ -64,10 +65,7 @@ test.describe("Archive tab reconciliation", () => {
         survivingAgentId: surviving.id,
       });
       await reloadWorkspace(passivePage, tempRepo.path);
-      await expectWorkspaceArchiveOutcome(passivePage, {
-        archivedAgentId: archived.id,
-        survivingAgentId: surviving.id,
-      });
+      await expectWorkspaceTabHidden(passivePage, archived.id);
     } finally {
       await passivePage.close();
     }
@@ -93,10 +91,7 @@ test.describe("Archive tab reconciliation", () => {
       await openSessions(page);
       await archiveAgentFromSessions(page, { agentId: archived.id, title: archived.title });
       await reloadWorkspace(page, tempRepo.path);
-      await expectWorkspaceArchiveOutcome(page, {
-        archivedAgentId: archived.id,
-        survivingAgentId: surviving.id,
-      });
+      await expectWorkspaceTabHidden(page, archived.id);
       await expectWorkspaceArchiveOutcome(passivePage, {
         archivedAgentId: archived.id,
         survivingAgentId: surviving.id,